Flexplate Remove and replace, closeups

[92DripCherokee]

I've got more pictures yet to shoot, these actually focused.

The other way to kill a transmission E-12 torx, through the shifter opening. I used an E-14, gave some extra wobble. The E12 couldnt bite it, the torx head was twisted out of shape!

From the top side, showing socket had a shallow grab, marginal angle

This is the setup, with 20" and two 3" inch extensions. fed in from engine side. At the end of tear down, it was only the pair of 7/16 -14 bolts, and the trans was free to slide. The engine stayed dead level, motor mounts stayed on. Got a jackstand propping up the engine, but it never pitched over.

The torque converter, dust from threadlocker outlines wallowed flexplate bolt holes. Front seal is doing fine, no leak.

The cracked flexplate, bleeding from cracked bolt pattern.
The noise this made was NASTY. I hate this thing like a wart.

The cracks run on the outer extreme of the bolt circle. They didnt meet up, the center was held by a 3/16 wide segment. Every broken flexplate sounds unique. Very chaotic, this never sounded like a rod knock. Loose converter bolts sounded like rod. This sounded like severe crank walk.

 

[blue95xj]

Thanks for the tips and pictures!! Now I have a good visual for when I do mine.
Mine definitely sounds like a rod but I know better.

 

[92DripCherokee]

Getting the E-12 bolts from the inside had a distinct advantage. There was no wobble joint in the extension, and being fairly short at 2 feet, it didn't twist much. The torx popped on the first try, very cool. Only took 20 minutes to remove the console, and gear shifter. Dropping the engine to get at the upper bolts is equally effective, I just did'nt want to wrangle both engine and transmission together. Turns out, the transmission and transfer case are relatively lightweight!

Removing the front pipe was the best. Expected a battle royale.
I used water instead of penetrating oil, and only a few minutes ahead of putting a wrench to the bolts. Easily turned all of the rusty things out. Only 2-1/2 years in place probably helped.

Some of the OEM part numbers for a 91-99 HO XJ

flexplate 52117761

reinforcing ring J321 4094

6 crank bolts J315 1407 Hex Head, .50-20x.56

4 torque converter bolts 3420 2497 M10x1.50x14 (there's a newer part number for these, on my sales receipt)

2 exhaust gaskets
1 donut 5200 5431
1 square 5201 7817

oring for trans dipstick tube joint 5300 3977

Got aftermarket u-joint straps from Napa, and the unions that screw into the transmission. Many stories here of leaks and breakage after removal. Things have a rare metric thread M14 x 1.5

http://www.napaonline.com/NOLPPSE/(S(apz2wo45lw44cp45wlazuw45))/Detail.aspx?R=BK_7304978_0229632683

Ace hardware has 5/16-24 x 1 1/4 grade 8 bolts with 1/2 inch hex heads, for the front driveshaft to transfer case yoke.

Between Ace, Advance, and tractor supply, every other bolt is available,

 

[Justpunchit]

What would cause a flex plate to crack like that? I hear a crazy knocking after I shut my engine off sometimes I wonder if that could be the issue.

 

[92DripCherokee]

The flexplate cracked for one certain reason

The two big 7/16-14 transmission bolts had backed out, and there was only 1 upper torx bolt left. The transmission was separated from the engine by close to 1/8 of an inch. That'll do it. I drive it hard and likely made it worse. A small angle like that puts a side load on the flexplate. Amazing the transmission front seal stood up to punisihment.

The hayseed who installed my reman motor 3 years ago never used loctite, or degreased the threads. Probably never tightened anything to spec anyway.

Here's some other common reasons I've learned

extremely heavy loads like towing or rock crawling
crankshaft walking in and out on the main bearings
off-balance torque converter
loose crankshaft to flexplate bolts
grinding the starter, bends the plate, causes vibration and later cracking
simple overrevving, too much centrifugal force

 

[Justpunchit]

Maybe my problem. But not likely now. My search continues.... But good write up.

 

[92DripCherokee]

http://www.youtube.com/watch?v=VEcXQ4jjxZI

this the sound, knocked at start up and shutdown
got much worse than this, it was tolerable at the stage you'll hear in this clip.

 

[Justpunchit]

phew, nope not mine doesn't sound like that. it only does it sometimes after shut down, knocks like theres a bolt or something rattling around somewhere.....it's really wierd.....

 

[92DripCherokee]

might be the exhaust hitting the crossmember.